Liu Shihong, Yang Yan, Wei Fang, Duan Jifa, Braynen Janeen, Tian Baoming, Cao Gangqiang, Shi Gongyao, Yuan Jiachen
School of Life Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, Henan, People's Republic of China.
Theory Biosci. 2017 Dec;136(3-4):199-206. doi: 10.1007/s12064-017-0252-3. Epub 2017 Jun 13.
Polyploidy is a widespread feature of plant genomes. As a typical model of polyploidy, autopolyploidy has been postulated evolutionary dead ends and received little attention compared with allopolyploidy. For the limited data available so far, the evolutionary outcome of genome diversity in autopolyploids remains controversial in comparison with its diploid ancestors. In the present study, the effects of autopolyploidy on genome diversity were revealed at a genome-wide scale by comparative analyses of polymorphism between Arabidopsis autopolyploids (autotetraploids and autotriploids) and related diploids within the first ten successive inbred generations using amplified fragment length polymorphism. The results showed that in contrast with diploids, the rapid genomic changes (including gain and loss of DNA sequences) in autopolyploids were definitely found within the first generations after autopolyploidization, but slow down and probably stabilized in the higher generations as a source of genetic diversity in the long term. The sequencing of these DNA fragments indicated that these changes occurred both on genic and inter-genic (or intronic) regions, and quantitative PCR showed that the expression of some corresponding genes in the genic regions was obviously affected (including upregulation, downregulation and silencing) in autopolyploids. Therefore, this study demonstrated that autopolyploidy could lead to rapid genomic changes and probably influence expression and function of certain genes within the first generations, giving rising to genetic diversification after polyploidization.
多倍体是植物基因组的一个普遍特征。作为多倍体的典型模型，与异源多倍体相比，同源多倍体被认为是进化的死胡同，受到的关注较少。就目前有限的数据而言，与其二倍体祖先相比，同源多倍体基因组多样性的进化结果仍存在争议。在本研究中，通过对拟南芥同源多倍体（同源四倍体和同源三倍体）与其相关二倍体在前十个连续自交世代中使用扩增片段长度多态性进行多态性比较分析，在全基因组范围内揭示了同源多倍体对基因组多样性的影响。结果表明，与二倍体相比，同源多倍体在多倍体化后的第一代中确实出现了快速的基因组变化（包括DNA序列的增减），但在更高世代中变化减缓并可能趋于稳定，从长远来看，这是遗传多样性的一个来源。对这些DNA片段的测序表明，这些变化发生在基因区域和基因间（或内含子）区域，定量PCR显示同源多倍体中基因区域一些相应基因的表达受到明显影响（包括上调、下调和沉默）。因此，本研究表明同源多倍体可导致快速的基因组变化，并可能在第一代影响某些基因的表达和功能，从而在多倍体化后产生遗传多样化。
